1. Field of the Invention
The present invention relates to a sealing material for a honeycomb structure, a honeycomb structure and a method for manufacturing a honeycomb structure.
2. Discussion of the Background
In a honeycomb structure used as a filter for removing particulates and the like from exhaust gases discharged from an internal combustion engine such as a diesel engine, or as a catalyst supporting carrier for removing toxic components such as HC and CO from the exhaust gases, inorganic fibers have been used as materials for various constituent members.
Specific examples thereof includes a sealing material containing inorganic fibers such as a sealing material (adhesive) for combining a plurality of honeycomb fired bodies to form a ceramic block and a sealing material (peripheral sealing material) to be formed on the periphery of a ceramic block.
In the case when such inorganic fibers remain in the human body, in particular, in lungs or the like, they might be harmful to the human body. Therefore, the inorganic fibers used in the sealing material are desirably highly safe to the human body.
WO 05/110578 A1 has described a sealing material containing, as inorganic fibers, at least one kind selected from the group consisting of an alkali metal compound, an alkaline earth metal compound and a boron compound.
The compounds included in the inorganic fibers, described in WO 05/110578 A1, are so-called biosoluble fibers. The biosoluble fibers are soluble in physiological saline solution. Therefore, even when taken into the human body, the biosoluble fibers are dissolved and discharged out of the body, and are subsequently considered to be highly safe to the human body.
The contents of WO 05/110578 A1 are incorporated herein by reference in their entirety.